MRI (magnetic resonance imaging) was first introduced in the United States in the early 1980s. It is the most important neuroimaging test in epilepsy because it shows more details of the brain's structure than does a CT scan.

MRI produces a remarkably accurate picture of the brain's structure. The images are extremely helpful for identifying scar tissue, areas of abnormal brain development (dysplasia), small brain tumors, blood vessel abnormalities, and changes in the brain's white matter.

MRI does not use x-rays.

The test makes computer images of the brain by means of a strong magnetic field and pulses of radio waves.

There are different strengths of MRI called Tesla (T). There are 1.5 T and 3 T MRIs with the higher number MRI providing more information.

fMRI, or Functional MRI, is a special MRI done to identify important areas of the brain, such as language or motor areas.